Preheat your oven to 330 degrees.
Combine your flour, salt, and baking powder in a bowl and set aside.
Combine your room temp buttermilk and vanilla extract in a bowl and set aside.
In your stand mixer fitted with your whisk attachment, whip your butter and sugar until light in color.
Add your room temp egg and mix it to combine.
Add half of the dry ingredients to the mixer on low speed, when combined add 1/2 of the wet ingredients. Repeat.
Scrape down the bowl to make sure everything is incorporated and allow it to mix 10 more seconds. Do not over mix the batter.
Remove the bowl from the stand and add the Dalgona mixture. Fold it into the batter until well combined.
Prepare your cake pans by spraying the edges with non stick spray and add a parchment round to the bottom.
Divide your batter evenly into the cake pans and cover them with aluminum foil.
Bake your cakes at 330 degrees until they are done. A toothpick inserted in the center will come out dry and the edges will start to slightly pull away from the pan. Mine took about 70 minutes.
Once baked remove them to a cooling rack and let them cool for about 10 minutes or until they are cool enough to remove from the pans.
Let cakes cool completely on a cooling rack.
Once cakes are totally cool I recommend wrapping in plastic wrap and freezing to decorate cake from frozen.****
Basic cake assembly is outlined in the above blog post.